The presidential campaign is a highly serious matter, of course. But to any observer who can manage the slightest bit of detachment, the candidates' strategy and tactics are a constant source of comedy.

Earlier this year, the challenge for former Massachusetts Gov. Mitt Romney was to prove that he was a genuine Republican tough guy on foreign policy. So Romney promised to "double Guantanamo." A leaked campaign memo laid out how such red-meat rhetoric would help sell his message of "Hillary=France." We are not making this up.

Now it's Sen. Hillary Clinton's turn at hilarity. After the New York senator's strong showing in Tuesday's primaries, her rival, Sen. Barack Obama, D-Ill., understandably toughened his rhetoric and called for Clinton to release her tax returns - something both she and Republican nominee John McCain should do immediately.

This predictable, legitimate salvo by Obama prompted this response from Howard Wolfson, Clinton's chief spokesman: "I for one do not believe that imitating [Whitewater special prosecutor] Ken Starr is the way to win a Democratic primary election for president."

Many Democrats believe Starr was on a partisan witch-hunt when he pursued and won the impeachment of Bill Clinton. So now we're supposed to think that any criticism of Hillary Clinton is tantamount to a partisan witch-hunt? The mind reels.